[postgis-users] ST_Union (8.4) and TopologyException

Simon Greener simon at spatialdbadvisor.com
Fri Aug 7 22:37:40 PDT 2009

To those who asked for a test case.

I prepared and sent a test case to Regina to ensure it was a good test set before sending it on to the discussion list.

Regina tested it and reported to me that:

"I tested this against GEOS 3.2 SVN and it worked.  Against GEOS 3.1.1 it doesn't."

I was running GEOS 3.1.1 as part of the standard PostGIS 1.4 on PostgreSQL 8.4 combo.

Regina provided me with the compiled GEOS 3.2 libraries:

SELECT postgis_full_version();
"POSTGIS="1.4.0" GEOS="3.2.0-CAPI-1.6.0" PROJ="Rel. 4.6.1, 21 August 2008" USE_STATS"

I can confirm that my data is now successfully processed by PostGIS's ST_Union though it isn't all that fast:

"Query returned successfully with no result in 5011922 ms." = 1hr 23min which is pretty slow.

Any idea why?

SpatialDB Advice and Design, Solutions Architecture and Programming,
Oracle Database 10g Administrator Certified Associate; Oracle Database 10g SQL Certified Professional
Oracle Spatial, SQL Server, PostGIS, MySQL, ArcSDE, Manifold GIS, FME, Radius Topology and Studio Specialist.
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